A mix of desert climate, high performance goals and the insight of a leader in sustainable design has yielded one of the first LEED Gold-certified straw-bale buildings in the world. Resource- and energy-efficient, the Santa Clarita Transit Maintenance Facility designed by HOK exceeds California Energy Efficiency Standards by more than 40 percent, securing a new standard for straw-bale in high performance building design.
The new transit facility was created as part of a citywide initiative to reduce hydrocarbon and ozone emissions from vehicles. The project’s intention is to serve the conversion of the city bus fleet from diesel to compressed natural gas and offer a publicly accessible CNG fueling station.
HOK led the integrated design project to meet high sustainability goals within a modest budget and on a challenging desert site prone to seismic activity. Using straw bales for wall infill targeted the need for a durable, low-cost, non-toxic, highly insulating material suitable to the extreme climate of the region.
HOK coupled high-recycled-content engineered wood with the characteristic thickness of straw-bale building design to allow structural elements to act as finished surfaces, minimizing the need for finish materials. With a focus on insulation, the team combined the thick straw-bale walls with high-performance glazing and a highly insulated roof to produce a building envelope that shields interior spaces from extreme solar gain and regulates indoor temperature.
An efficient water-source heat pump uses an on-site cooling tower to deliver conditioned air via a highly efficient under-floor distribution system that can be moderated at each individual workspace. The system uses the cool nighttime desert air to precondition interior spaces against the hot, desert days. Light colored exterior finishes and generous natural daylighting help to further reduce energy and heat loads
Inside the transit facility is a showcase for indoor environmental quality with wheat straw board casework and millwork. Recycled, renewable, low-toxic and locally sourced materials were used throughout the building in keeping with the low toxic, sustainable qualities of the straw-bale infill.
The designers opted for a solar photovoltaic canopy to shade buses and provide almost half of the building’s annual energy needs. An electronic monitoring system tracks thermal comfort, energy efficiency and moisture levels ensuring the owner can continually improve on the building’s operating performance. + HOK + USGBC LEED + California Energy Commission